Conventionally, in a virtual try-on of an item, such as a virtual pair of glasses displayed on a recorded image of a person's face, if the shadows casted by the glasses are not visible on the person's face, then the effect of the try-on is missing an important element of realism. Typically, a shadow on an image can be generated using ray tracing. To generate a shadow of an object (e.g., a virtual pair of glasses) on a person's face, an exact model of the person's face, including a texture that represents the person's face, may need to be generated before ray tracing can be performed. However, not only is generating such a detailed model of the person's face time consuming, the process of ray tracing a shadow onto the exact model is also very laborious and inefficient.